Chapter III Program Flow control

3.1 Program Flow control

• Judging structure

• Select structure
  

• Loop structure

3.1.1 Judgment Structure

If statement

Three different formats:

1. if (conditional expression) {

Execute the statement;

}

2. if (conditional expression) {

Execute the statement;

} else {

Execute the statement;

}

3. if (conditional expression) {

Execute the statement;

} else if (conditional expression) {

Execute the statement;

}

......

else{

Execute the statement;

}

If the statement of the control is only one, you can not {}; that is, if the if does not have {}, it only controls the statement closest to it.

3.1.2 Selection structure

Switch statement

switch (expression) {

Case takes value 1:

Execute the statement;

Break

.......

Case Value N:

Execute the statement;

Break

Default

Execute the statement;

}

An expression accepts only 4 types of values: byte, short, ING, char

The case is the matching value, if the matching walk, the corresponding execution statement; If all do not match, go to default.

Break indicates that the selection is out of bounds, and if it does not break, it will continue to execute down without judging the case after it has been matched.

The location of all case and default can be arbitrary.

3.1.3 Cycle structure

For, while, do and

1. For

for (initialization expression; loop condition; post-loop operation) {

Loop body (execution statement);

}

2. While

while (conditional expression) {

Loop body (execution statement);

}

3. Do While

do{

Loop body (execution statement);

}while (conditional expression);

Features: The loop body executes at least once, regardless of whether the condition is satisfied.

3.1.4 The simplest form of the infinite loop

for (;;) {}

while (true) {}

This article is from the "Java Basics" blog, so be sure to keep this source http://8163413.blog.51cto.com/8153413/1689727

Chapter III Program Flow control